Triboluminescence
by microgirl
Summary: How LifeSavers keep the spark in a relationship...GSR


_Triboluminescence_

_Spoilers: Way to Go (though there are no direct references)_

_Disclaimers: I don't own anything or anyone in regards to CSI; the show and its characters belong to a bunch of people who aren't me. However, I am the proud owner of a Grissom straw hat thanks to EllipsesBandit :) Despite what many people say, I think the hat is cool!_

_Author's Note: This fic was inspired by something I did in a physics class. I even emailed my old physics teacher to make sure I had the facts correct (thank you Brian). But among the little bit of science there is fluff, because if you've read my other stories, you know that I'm a fluffist._

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"At least M&M's aren't boring like Twix. They're colorful. There's red, blue, green, yellow, orange, and brown. AND there are more fun colors around the holidays. At Easter there's pink and purple and sky blue and-"

"But M&M's are just milk chocolate. Twix you get chocolate, caramel, and cookie. What better combination could you ask for?"

"Ah, Nicky you're forgetting there are Peanut M&M's, Peanut Butter M&M's, and Crunchy M&M's."

"Twix isn't your typical candy bar though. You always get two of them. Twice the taste."

"Does Twix have a cool little 'M' on it?"

Rolling her eyes at the mindless argument, Sara continued her paperwork. Earlier that evening herself, Nick, and Greg had investigated a robbery at a small candy store. On the drive back to the lab, Nick and Greg had started talking about their favorite candies. That of course led to the discussion about the sweets that were the best, which she had to endure as she sat in the break room as they completed their forms.

She managed to tune out most of the conversation, but her ears picked up Greg's words: "We could always ask Sara to settle this."

"No you don't," she told him, not looking up from the file.

"C'mon," Greg pleaded. "You've got to have an opinion on the greatest candy."

She glanced up, and gave him a half smile. "Not really."

"Maybe Twix and M&M's isn't her thing," Nick said. He leaned forward in his chair. "So what is your favorite candy?"

She regarded him for a moment before she answered. People always gave her strange looks when she told them she loved this candy. "LifeSavers."

Greg nodded his head, as if in some kind of agreement. "Not bad, not bad. They're colorful too. You get different fun fruit flavors. And if you swallow it wrong, you can still breathe. They definitely live up to their name."

"I'm not talking about the fruit flavored kind. I like the wintergreen ones."

Nick tried his best to hide his smirk, but part of it shone through. Greg didn't bother being discreet about his reaction; he laughed loudly.

"You know Sara," Greg began, "you had major points before, but those went completely down the tubes. Wintergreen LifeSavers are just white and they're a boring mint." He shrugged. "Sorry, but our candies still outrank yours."

"Can Twix or M&M's spark in your mouth?" She smugly pointed out.

Nick's forehead wrinkled in confusion. "What?"

"Wintergreen LifeSavers spark in you mouth," she repeated.

Greg casually tossed his pen on the open file in front of him. "No way. How does that happen?"

She started writing again. "Triboluminescence."

"Tribo-what?" The wrinkles deepened on Nick's face

"Triboluminescence. It means the material, in this case the LifeSaver, produces light upon being scratched, crushed, or rubbed."

"All right, how exactly does that work?" asked Greg.

"When you chew the candy, the sugar crystals rub together and make a voltage between them. This makes a spark jump, ionizing the nitrogen in the air. The ionized nitrogen glows, mostly in the ultraviolet range, but a small fraction is in the visible region. The UV makes the methyl salicylate, the minty flavoring, fluoresce. Hence, you get a green or blue-green flash."

Nick rubbed his chin for a moment. "And you can actually see this?"

Leaning back in her chair, Sara answered, "It's not a huge spark, but you can usually see something." When the men glanced at each other with thoughtful expressions, she playfully added, "So Greg, who wins now?"

The young man grunted in response. "Figures you would find some science thing with candy. Now you have to have some sort of chocolately favorite right?"

Ignoring his question, Sara peeked at her watch, realizing that shift was over. A year ago she wouldn't have thought twice about staying. Now, she was more than happy to leave on time. While she gathered her files, Greg rattled off what candies he thought she liked.

"Reese Cups? Crunch Bars? Caramello? Milky Way?"

Nick shook his head in amusement, and continued writing. Stopping his inquiry, Greg looked hopefully at her for a reply. She smiled and said, "Bye guys. See you tomorrow."

As she walked to the door, Greg yelled, "I've got it! I bet you're a Snickers fan!"

She turned around, her expression deadly serious. "I have _never_ liked Snickers."

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She pulled her vehicle up onto the driveway, pleased to see both Grissom's Denali and Audi parked in front of their new house. Hopefully he had breakfast cooking and unpacked a few boxes. Well, she'd at least settle for breakfast.

When she walked in the house, the sweet aroma of blueberry muffins filled the air. On the end table next to the front door, she noticed a green bag with a small red bow stuck to it. Sara started chuckling when she picked up the bag; it was filled with Wintergreen LifeSavers. Just then, Grissom walked out of the kitchen with a pleased smirk.

She held up the mint candies. "What's this about?"

He only shrugged. "I heard they're your favorite."

"How did you find that out?"

"I have my sources."

They sat at the table with their food, having a friendly argument about decorating the house. While she washed the dishes, she heard the bag rustling as he sat down with the LifeSavers.

"I didn't know LifeSavers possessed the property of triboluminescence," he called over the running water.

"Now that's hard to believe." She placed the last glass in the dishwasher.

"It's true."

She found it difficult to imagine that he didn't know this obscure fact since he seemed to know all the other obscure facts of the world. But if that was true…

"Then I'm surprised the bag wasn't already opened when I got home."

She looked up from the sink to see his furrowed eyebrows and his mouth somewhere between a smile and a frown.

"I know how like to do your experiments," she defended.

"I would need your assistance anyway. I don't know the proper setting to see this spark."

After starting the dishwasher, she walked around the counter to stand in front of him. She dried her hands with a red checkered towel. "All you need is someplace dark, and a mirror to watch your mouth or another person so you can see the spark in theirs."

His eyes twinkled with excitement, but he spoke with a straight face. "Would you be my other person for this experiment?"

"Of course," she grinned.

"All we need is a dark place? Doesn't have to be anywhere specific?" He acted as though they needed to be in a special atmospheric chamber.

"Just somewhere that's very dark."

Grinning like he was about to take a pint of blood from a co-worker he said, "I know the perfect place; quiet, comfortable, and extremely dark."

"Really?" She crossed her arms over her chest. "And where is it?" She briefly wondered if his "perfect place" involved a certain room upstairs. Then again this was Gil Grissom; he took his research seriously.

"We'll go there tonight," he stated, not bothering to answer her question. He got up from the table, and walked to the stairs. He stopped about halfway up, then added "Dress warmly too. The woods tend to get cold at night."

Yes, Gil Grissom didn't fool around with experiments.

* * *

With the Strip miles behind them and moon in its waning crescent phase, the trees on either side of the dirt road appeared to be almost black in the darkness. An endless sight of stars dotted the night sky. The air became cooler, enough for Grissom to turn on the heater as he drove himself and Sara through the forest. After traveling for several miles, he gently eased the car off the dirt road to a small clearing under a couple of tall pine trees. He was quite familiar with the area as he had gone there often to study the constellations.

Once they settled in the back seat, he draped a fleece blanket over his and Sara's laps. Even though they both wore jeans and heavy sweatshirts, he wanted to make sure they stayed warm, especially since he didn't leave the engine running.

She pulled open the bag of minty treats. "You ready to do this?"

"Absolutely," he smirked.

"Okay," she answered brightly. "Here we go." She unwrapped the LifeSaver, and he leaned in closely to her face. When he nodded, she crunched the candy between her teeth.

Pulling back with a little frown, he shrugged. "I didn't see anything."

"You didn't?" She exclaimed after she swallowed the candy. "Sometimes the spark is hard to see. We'll try again." He scooted closer until his nose was about an inch from her's making her chuckled lightly. This time when she chewed he saw a tiny, but distinguishable blue flash.

His face lit up as if he had just discovered a new species of beetle. "I saw it!"

Her brown eyes sparkled at his enthusiasm. Before she could respond he blurted, "Let me see that again."

Again he got close to her with that endearing concentrated expression of his, and smiled when he noticed the flickers of light.

Handing Grissom a wrapped LifeSaver, she informed him, "Now it's your turn."

For the next twenty minutes they talked and laughed in between watching each other munch on the candy. Closing on the house, moving in, and ongoing cases at the lab had left the pair stressed for the last couple of weeks. Grissom was pleased they could spend a carefree evening together, just simply being with each other.

As he was about to pop another LifeSaver in his mouth, he heard knocking on the window behind him. He turned to see someone standing outside the car. He put a hand up to shield his eyes from the offending light, and caught a glimpse of a park ranger's badge. The man stepped back when Grissom opened the door.

"Good evening," the ranger began. "May I ask what you two are doing in the back seat?"

"We're in the middle of an experiment," Grissom deadpanned.

"Uh huh. And what kind of experiment would that be?"

"Triboluminescence," Grissom said, like it was nothing out of the ordinary. "With LifeSavers."

The park ranger's face scrunched up in utter puzzlement. He opened his mouth to say something, but no words came out. Finally the man looked past Grissom, and directed his question to Sara. "Ma'am is that true?"

"Yes it's true. We're just sitting back here trying to see the candy spark in our mouths," she replied just as seriously as Grissom had a moment ago.

The ranger squinted and blinked quizzically at the pair. Grissom continued to stare at the man waiting for more questions, but none came.

Finally he spoke again. "Right…Well, ummm…You're not supposed to park your car off the path here. There's a campsite about two miles up the road if you…want to continue your…experiment there."

"No problem," Grissom answered easily. "We're about done anyway."

"Have a goodnight then." The ranger shook his head as walked back to his car.

The second Grissom turned to face Sara again they both burst out laughing. As soon as they gained some control, the laughter would start again. The cycle lasted a few minutes until both of them eventually calmed down.

"I have to say that's the first time I've ever been caught in the backseat with a guy." Wiping the tears at the corners of her eyes, Sara added in a mock pout, "For doing an experiment of all things!"

He smiled at her words. "It's the second time I've been caught in the backseat."

"When was the first time?"

"High school," he said putting his arm around her. "I was parked on a path by the beach. The officer came up when he saw the windows steamed and the car rocking. Then I'm sure he heard the cussing and the yelling." Her facial expression changed from one of delight to that of surprise. There was also a tinge of anger as she probably didn't want to hear a detailed description about his escapades with another woman. "I just couldn't find the lens cap to my telescope."

She giggled again, and then trailed her left hand along his beard. His felt his heart rate increase as he gazed in to her maple-colored eyes.

"I've got another experiment for you," she whispered huskily.

"What is it?"

"Sensory input," she said before she descended on his lips.

Her skin felt smooth and soft as he cupped her cheek. The sweet, mint flavor of her mouth left him wanting to taste her kisses forever.

Of all the experiments Grissom had done, this one was by far the best.

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The End


End file.
